1. Field of the Invention
The present invention relates to a cassette loading apparatus of a front loading system which can be used in a magnetic recording and reproducing system, such as a video cassette recorder.
2. Statement of the Related Art
In recent years, a front loading system in which a cassette is inserted at a front surface has been mainly used for the cassette loading apparatus of a magnetic recording and reproducing system, such as a video cassette recorder. Description will be made below of an example of a conventional cassette loading apparatus with reference to FIG. 1.
FIG. 1 is a perspective view of a conventional cassette loading apparatus. In FIG. 1, a cassette holder unit 1 detachably retains a cassette which contains magnetic tape. Side frames 2, 3 (hereafter referred to as the "side plates") are disposed on both sides of the cassette holder unit 1 and are provided with L-shaped guide grooves 8, 9 and 10, 11 with which pins 4, 5 and 6, 7, projecting respectively from both ends of the cassette holder unit 1, are engaged.
Drive arms 12, 13 respectively have guide holes 15a for moving the pins 4, 5 to the positions, 4a, 5aindicated by dotted lines, and are rotatably supported on both sides of the side plates 2, 3 respectively. A drive motor 16 drives an intermediate gear 19 via a worm gear 17 and a worm wheel 18. The intermediate gear 19 is fixed to one end portion of a shaft 20 rotatably supported by the side plates 2, 3 and meshes with a gear portion 12a formed in a proximal portion of the drive arm 12. Meanwhile, the other intermediate gear 21 is secured to the other end portion of the shaft 20, and this intermediate gear 21 meshes with a gear portion of the other drive arm 13. A cassette guide 22 guides the insertion of the cassette into the cassette holder unit 1 and connects the side plates 2, 3. A top plate 23 is connected to the side plates 2, 3 from the top, and is provided in such a manner as to maintain the rigidity of the overall cassette loading apparatus.
As is apparent from the above-described arrangement, the path for transmitting the power from the drive motor 16 to the cassette holder unit 1 is arranged in the order of the drive motor 16, the worm gear 17, the worm wheel 18, the intermediate gears 19, 21, the drive arms 12, 13, the pins 4, 5, and the cassette holder unit 1.
With the above-described arrangement, however, when the cassette is manually inserted, there has been a drawback in that, if the cassette is pushed in more than is required or impulsively after the automatic operation of pulling in of the cassette holder unit 1 by the drive motor has been commenced, a load corresponding to the pushing force is applied to the parts constituting the power transmission path This results in damage to some parts of the power transmission path and may cause disengagement of these parts.